This application is based on and incorporates herein by reference Japanese Patent Application No. 2000-339262 filed on Nov. 7, 2000.
1. Field of the Invention
The present invention relates to a discharge lamp device having a discharge lamp and a circuit unit for applying a high voltage to the discharge lamp.
2. Description of Related Art
For example, a headlight device 100 of a vehicle shown in FIG. 6 has been previously proposed as a discharge lamp device having a discharge lamp as a light source. The headlight device 100 includes a casing 101 that receives the discharge lamp 110 and a circuit unit 120 therein. The circuit unit 120 supplies a high voltage of about 20 kV to the discharge lamp 110 to light the discharge lamp 110. The discharge lamp 110 and a circuit unit 120 are electrically connected together through a high voltage wire 125.
In this arrangement where the discharge lamp 110 and the circuit unit 120 are connected together through the high voltage wire 125, the high voltage wire 125 needs to be sealed in order to prevent generation of noises from the high voltage wire 125. Furthermore, a high voltage connector 126 is required to connect the high voltage wire 125 to the discharge lamp 110. This generally causes an increase in manufacturing cost.
In view of the above disadvantages, it is conceivable to directly connect the discharge lamp to the circuit unit to make an electrical connection therebetween without using the high voltage wire. In such a case where the discharge lamp and the circuit unit are directly connected together, the high voltage connector and the high voltage wire can be advantageously eliminated.
However, if the discharge lamp and the circuit unit are directly connected together, and thereby the circuit unit is positioned adjacent to the discharge lamp, heat generated from the discharge lamp and from the circuit unit causes a rise of temperature in the circuit unit. This may cause malfunctions of circuit elements in the circuit unit.
Thus, an objective of the present invention is to provide a discharge lamp device capable of preventing a circuit unit from getting a high temperature that causes malfunctions of the circuit unit, while eliminating a high voltage wire and a high voltage connector.
To achieve the objective of the present invention, there is provided a discharge lamp device including a discharge lamp, a circuit unit and a heat radiating member. The circuit unit is directly connected to the discharge lamp to apply a high voltage to the discharge lamp. The heat radiating member radiates heat generated from the discharge lamp and the circuit unit. The heat radiating member radially extends in at least one direction from one of the following: (I) a connection between the discharge lamp and the circuit unit; and (II) the circuit unit.